In the optical fiber field, there is a need to connect the optical transmission path of a fiber or device to that of another fiber or device. Often this connection is effected by inserting a plug into an adapter. As used herein, the term “adapter” refers to any structure that facilitates fiber/fiber, device/fiber and device/device interconnections. An adapter generally comprises a housing, or portion of a housing, having a port which is configured to receive and hold a plug to facilitate the plug's optical connection with another plug or other device which connected to the adapter. The plug typically comprises a plug housing and a ferrule or other means for holding and precisely positioning one or more fiber ends. When the plug is inserted in the adapter, the adapter and plug are “mated.” Likewise, when the plug is not inserted in the adapter, the adapter and plug are “unmated.” Specific types of adapters include, for example, connector couplings which facilitate the connection of two plugs. Such couplings may have various configurations (e.g., simplex, duplex and quad) for use in various applications (e.g., backplane and through-chassis interconnections). Another important type of adapter includes those that are attached to or integral with a device to facilitate the optical connection between the device and a plug. Typical devices include, for example, active devices, such as transceivers and transmitters, and passive devices, such as attenuators and multiplexers/demultiplexers.
Often adapters are used to facilitate the connection of an optical connector plug to another connector plug or device contained within a chassis. The term “chassis” as used herein broadly refers to a containment structure for housing electrical components or switching components. The connector assembly is typically mounted in a chassis or housing through an opening which is slightly larger than the housing of the adapter. The adapter is attached to the chassis using fasteners which extend through mounting holes in the tabs which extend from either side of the adapter. Although effective in securing an adapter to a chassis, this mounting configuration may be susceptible to EMI leakage.
Reducing EMI emissions is becoming more important as operating frequencies increase. Although EMI does not affect optical components, other electronic equipment used in conjunction with optical components may be sensitive to EMI noise or may generate EMI noise. Accordingly, it is preferable that the chassis be designed to prevent passage of EMI radiation. Unfortunately, adapter openings in the chassis are sources of EMI leakage. For example, the MU adapter requires an opening of approximately ⅝″ by ⅜″. Furthermore, a chassis will typically have a series of openings to accommodate a multitude of adapters thus compounding the EMI leakage problem. 
One common prior art approach for providing EMI shielding around adapters is to cover the connector assembly with an electrically-conductive shroud or boot. Although this provides reduced EMI leakage, it requires space within the chassis to accommodate the EMI boot. This is problematic since space within the chassis is usually limited. Furthermore, as the complexity of equipment increases to accommodate more fibers, space within the chassis will become even more precious.
Thus, there is a need to provide EMI shielding for adapters without consuming a significant amount of space. The present invention fulfills this need among others.